Assessment of patient perception of glaucomatous visual field loss and its association with disease severity using Amsler grid.

PURPOSE

To investigate patients' perception of glaucomatous VF loss and its association with glaucoma severity using the Amsler grid test.

METHODS

In this prospective cross-sectional study, glaucoma patients with abnormal 10-2 Humphrey Swedish Interactive Threshold Algorithm-standard VF tests were enrolled consecutively. All patients underwent a black-on-white Amsler grid test for each eligible eye. They were asked to outline any perceived scotomas (areas with abnormal grid lines) on the grid and then describe verbally their perception of the scotomas. Examiners asked patients to clarify their descriptions. All descriptions used by patients were recorded in their own words, which were then sorted into descriptor categories according to similar themes. The number of descriptor categories was counted for each eye. 10-2 VF mean deviation (MD) was compared among eyes that reported different number of descriptor categories. The mean 10-2 VF MD values were compared among different descriptor categories.

RESULTS

Fifty glaucoma patients (88 eyes) were included. Patients used a total of 44 different descriptors for their scotomas. Patients' descriptors were classified into categories that incorporated similar themes, resulting in 4 overarching descriptor categories: Missing/White, Blurry/Gray, Black, and Not Aware. Fifty-two eyes reported one descriptor category and 19 eyes reported two descriptor categories (mean number of descriptor categories = 1.27±0.45). Eyes that reported two descriptor categories had worse VF MD than those that reported one (-17.86±10.31 dB vs. -12.08±7.53 dB; p = 0.012). When eyes were organized according to its combination of descriptor categories, each eye naturally sorted into one of the following 5 groups, in frequency order: Missing/White (27 eyes; 31%), Blurry/Gray (21 eyes; 24%), combined Missing/White and Blurry/Gray (19 eyes; 21%), Not Aware (17 eyes; 19%), and Black (4 eyes; 5%). The mean 10-2 VF MD severity order was Black (-21.18±10.59 dB), combined Missing/White and Blurry/Gray (-17.86±10.31 dB), Missing/White (-11.92±6.76 dB), Blurry/Gray (-10.55±7.03 dB), and Not Aware (-3.91±4.05 dB) (p<0.001).

CONCLUSION

Paracentral vision loss in glaucoma is perceived by patients. As the perception of scotomas and the variety of terms to describe scotomas are related to glaucoma severity, clinicians should pay attention to patients' subjective descriptions of their glaucomatous VF loss. The historical notion that glaucoma patients lose their peripheral vision first and eventually look through a black tunnel needs to be updated to reflect the true perception of glaucoma.